The Cathedral Treasury presents one of the most significant collections of ecclesiastical art treasures, comprising remarkable works from Late Antiquity (relief showing a relic procession), works from the Romanesque era (portable altar with St. Andrew relic, Holy Nail shrine, Gozbert censer), works from the Gothic era, the baroque, and the 19th and 20th centuries (works in historism style from the Trier Brems-Varain Studio).

Additionally, there are several important medieval manuscripts (Simeon's Codex, Helmarshausen Book of Gospels, Kuno von Falkenstein's Pericope book), and a few liturgical vestments.